Reduced Order Modeling for Plasma Aeroelastic Control of Airfoils in Cascade: Dynamic Mode Decomposition

A dynamic mode decomposition is carried out for the flow field of a compressor cascade with plasma actuators employed for aeroelastic control. Numerical assessments carried out in previous works have shown that alternate triggering of pressure side/suction side actuators installed at the trailing edge of the blades can effectively reduce vibratory loads and enlarge the flutter boundaries of a linear compressor cascade. With the twofold aim of having an in depth understanding of the flow physics associated to plasma actuation and of developing an optimized control law for the actuators, the dominant structures of the pressure field are extracted via a dynamic mode decomposition. The decomposition is conducted on the actuated and non actuated pressure fields at several inter blade phase angles. The fundamental effects of plasma actuations on the flow field, and in turn on the blade loading, are identified and discussed. The procedure allows to get an useful picture of the main fluid mechanic phenomena associated to plasma aeroelastic control on turbomachinery bladings.